I decided to go with an aftermarket radio after I had problems with the factory navigation radio in my X5. The module for Bluetooth hands free for instance was bad when I bought my X5 so I bought a used one off ebay since new parts are not available for this anymore.
The replacement one from ebay worked for a week or so but started running the battery down all the time. With the cost of these used parts not being that cheap I decided I would rather have a new stereo with modern features vs used with old features and costly parts.
So I will break this down into sections covering information for the factory radio, aftermarket radio, and installation of the aftermarket radio.